1. Field of the Invention
The present invention relates to a method and a wireless communication system for managing information on locations of mobile stations and a location information providing system.
2. Description of the Related Art
In the conventional mobile communication system, a device for managing location of a plurality of mobile stations is provided, to store information about which area (called “location area”) each of mobile stations is located. When an incoming call directed to a mobile station occurs, the device identifies the location area. Next, the device generates paging signal to transmit to the mobile station via a switch covering the location area and one of the base stations belonging to the switch.
In the registration of a location area, firstly a mobile station receives information on location area. Secondly, the mobile station transmits a number to identify the mobile station and the location area information, via the base station and the switch. Especially, there is a location management system of a mobile station in a train. In such a system, a communication device is provided in a train, to collectively manage location registration of all mobile stations in the train (reference will be made to Japanese Patent Application No. H11-355835).
However, it is cumbersome and costs a lot to provide such device in a train capable of processing requests of location registration from many mobile stations. Even if such devices are introduced, base stations and switches still must process large amounts of request especially in an urban city where many trains run. Specifically, radio channels have to be allocated to exchange signals for location registration between a location registration server and mobile stations. Therefore, radio frequency bandwidth available for voice and data communication is restricted thereby communication traffic volume increases. It is often the case that a moving object such as a train or a bus moves to a place such as a tunnel into which a radio wave transmitted from a base station does not propagate. In this case the base station does not receives any signals either from the object and a mobile station in the object, so that the location server cannot recognize a location of the mobile station.
There is a system for providing location information stored in the location server to an external terminal. In such a system, a location of a mobile station can be tracked in real-time. In principle, it is possible to know a future location of a mobile station as long as a user of the mobile station get off a train. However, in the conventional system such information on future location cannot be provided.
The present invention, as its object, provides a wireless communication system at a low cost, in which locations of mobile stations moving together with an object such as trains and buses are tracked accurately and efficiently. In addition, the present invention provides a communication system for providing a fixture location of a mobile station to a third party.
To attain the above object, a method of the present invention for managing location information on a mobile station in an object by a server on a mobile network comprising the steps of:    upon receiving object identification information from a transmitting device provided in the object, the mobile station transmitting to the server received object identifying information and mobile identifying information for identifying the mobile station;    the server receiving and storing correspondingly the object identifying information and the mobile identifying information;    obtaining, from a traffic control device which controls movement of the object, object movement information of the object identified by the object identifying information;    converting the movement information into a location area information; and    managing location of the mobile station on the basis of the location area information.
In this method, a location of mobile station is tracked by transmitting a pair of mobile identifying information and object identifying information. It is not necessary to provide an expensive device, which can deal with registration requests from many mobile stations in an object at one time. It is only an inexpensive device for merely transmitting the object identifying information that is needed. Thus, this system can be established in at low cost. In a preferable embodiment, upon receiving a call for the mobile station, the server inquires about the movement information for the traffic control device. In another preferable embodiment the traffic control device notifies the server of the movement information when detecting movement of the object.
A method for communication in a communication system of the present invention having a server on a mobile network for communication with a mobile station and a traffic control device for controlling an object comprises the steps of:    upon receiving an object identifying information for identifying the object from a transmitting device provided in the object, the mobile station transmitting to the server mobile identifying information for identifying the mobile station and received object identifying information; and    the server receiving the mobile identifying information and the object identifying information;    storing the mobile identifying information and the object identifying information correspondingly;    when receiving a call for the mobile station identified by the mobile identifying information, retrieving the object identifying information corresponding to the mobile identifying information; and    transmitting retrieved object identifying information to the traffic control device; and    the traffic control device generating movement information on the object identified by the object identifying information; and    transmitting generated movement information to the server; and    the server converting received movement information into location area information; and    paging the mobile station on the basis of the location area information.
By using this method, it is not necessary to update registration of location every time a mobile station moves into another location area, once the object identifying information is registered with the server Therefore, radio traffic according to location registration is reduced.
In another embodiment, upon detecting a movement change of the object, the traffic control device generates movement information, transmits to the server the object identifying information and generated movement information. And the server receives the movement information, converts received movement information into location area information about an area within which the mobile station is located and stores the object identifying information and the location area information correspondingly. When receiving a call for the mobile station including the mobile identifying information, the server retrieves the location area information corresponding to the mobile identifying information and pages the mobile station on the basis of the location area information.
In this embodiment, the location server keeps the latest location area information on a mobile station. Therefore, the location server does not necessarily request movement information to the traffic control device, when a call for a mobile station is issued. Thus, identifying the mobile station to transmit a paging signal can be done quickly.
A communication system of the present invention has a traffic control device for controlling movement of an object and a mobile network. The mobile network comprises a mobile station, a base station for communicating with the mobile station, a switch for communicating with the base station, a location server for communicating with the switch, and an object information server for communicating with the location server and the traffic control device. The mobile station comprises means for receiving object identifying information for identifying the object and transmitting to the base station received object identifying information and mobile identifying information for identifying the mobile station. The location server comprises means for storing the object identifying information and the mobile identifying information correspondingly, both of which sent from the mobile station, means for retrieving and transmitting to the location server the object identifying information corresponding to the mobile identifying information, when receiving from the switch an inquiry of location area information on the mobile station including the mobile identifying information and means for receiving from the object information server and transmitting to the switch the location area information on the object identified by the object identifying information. The object information server comprises means for receiving from the location server and transmitting to the traffic control device the object identifying information, means for receiving from the traffic control device movement information on the object identified by the object identifying information, means for converting received movement information into the location area information and means for transmitting converted location area information to the location server. The traffic control device comprises means for receiving from the object information server the object identifying information and generating the movement information on the basis of received object identifying information and means for transmitting generated movement information to the object information sever.
In a preferable embodiment, the traffic control device comprises means for detecting movement change of the object and generating movement information representing movement of the object and means for transmitting to the object information server the object identifying information and the movement information. The object information server comprises means for receiving from the traffic control device the object identifying information and the movement information and converting received movement information into location area information representing an area within which the mobile station is located and means for transmitting to the location server the object identifying information and the location area information. The location server comprises a first storing means for receiving from the object information server and storing correspondingly the object identifying information and the location area information, a second storing means for storing correspondingly the object identifying information and the mobile identifying information, both of which sent from the mobile station and means for retrieving from the second storing means the object identifying information corresponding to the mobile identifying information, when receiving from the switch an inquiry of the location area information including the mobile identifying information.
Furthermore, it is possible that when not receiving from the transmitting device the object identifying information and moving into another location area, the mobile station transmits to the location server updated location information on the mobile station and the mobile identifying information. In addition, when receiving the location area information and the mobile identifying information sent from the mobile station, the location server stores to the second storing means the mobile identifying information and the updated location area information correspondingly, instead of the object identifying information.
An information providing system of the present invention for providing location information on a mobile station in a mobile network to a terminal comprises a location server in the mobile network for managing location of the mobile station and a location information server for carrying out communication with the terminal. Upon receiving from a transmitting device provided in an object identifying information for identifying an object, the mobile station transmits to the location server the mobile identifying information for identifying the mobile station and received object identifying information. The location server receives and stores correspondingly the object identifying information and the mobile identifying information sent from the mobile station. Upon receiving from the terminal an inquiry of location information on the mobile station including the mobile identifying information, the location information server judges whether the object identifying information corresponding to the mobile identifying information is stored in the location server. If the object identifying information is stored, transmits to the terminal boarding information representing that the mobile station is in the object By using the terminal in this system, a person can know that the mobile station is in the object.
In a preferable embodiment, the location information server further comprises means for identifying the mobile station using the mobile identifying information, carrying out communication with the mobile station, and obtaining from the mobile station the location information and transmitting to the terminal the boarding information and the location information.
In another preferable embodiment, the information providing system further comprises an object information server for carrying out communication with a traffic control device which controls movement of the object Upon receiving from the terminal an inquiry of location information including the mobile identifying information, the location information server transmits the mobile identifying information to the location server. Also, upon obtaining from the location server the location information, the location information server transmits to the terminal the boarding information and the location information. Upon receiving from the location information server the mobile identifying information, the location server transmits to the object information server the object identifying information corresponding to the mobile identifying information. Upon receiving the object identifying information from the location server, the object information server obtains from the traffic control device the movement information on the object corresponding to the object identifying information, converts obtained movement information into the location information, and transmits the location information to the location information server via the location server.
It is possible that when receiving from the terminal an inquiry of the location information on the mobile station, the location information server generates, on the basis of the movement information, estimated location information representing a future location on the mobile station and transmits the estimated location information to the terminal. In this system a person can obtain a future location of a mobile station in addition to the present location.
In another preferable embodiment, the object information server stores the movement information obtained from the traffic control device and the object identifying information correspondingly. When receiving from the location server the object identifying information, the object information server generates the location information on the object identified by the object identifying information on the basis of stored movement information on the object.
It is possible that upon detecting a movement change of the object, the traffic control device updates and notifies to the object information server of the movement information. Also, the object information server receives the movement information and generates the location information on the basis the movement information. A method of the present invention for providing location information of a mobile station in a mobile network to a terminal comprises the steps of:    the mobile station receiving, from a transmitting device provided in an object, object identifying information for identifying the object; transmitting to a server in the mobile network the object identifying information and mobile identifying information for identifying the mobile station;    the server storing the object identifying information and the mobile identifying information correspondingly;    when receiving from the terminal an inquiry of location information on the mobile station including the mobile identifying information, judging whether the object identifying information corresponding to the mobile identifying information is stored in the server; and    if the object identifying information is stored, generating and transmitting to the terminal boarding information representing that the mobile station is in the object.
In a preferable embodiment the server stores the object identifying information and the mobile identifying information correspondingly. When receiving from the terminal an inquiry of location information on the mobile station including the mobile identifying information, the server retrieves the object identifying information corresponding to the mobile identifying information, obtains movement information on the object identified by the object identifying information, converts obtained movement information into the location information and transmits the location information to the terminal.
It is possible that when receiving the movement information, the server generates, on the basis of the movement information, estimated location information representing a future location of the mobile station and transmits the estimated location information to the terminal.